<f:form.validationResults for="{object}">
    <f:if condition="{validationResults.flattenedErrors}">
        <ul>
            <f:for each="{validationResults.flattenedErrors}" key="propertyPath" as="errors">
                <li>
                    {propertyPath}:
                    <ul>
                        <f:for each="{errors}" as="error">
                            <li>{error}</li>
                        </f:for>
                    </ul>
                </li>
            </f:for>
        </ul>
    </f:if>
</f:form.validationResults>